Fixed weird logic in get_next_non_blank_line and skip_to_next_blank_line. Removed expensive regex in exchange for simpler and faster char checks.

Author: SimonCahill

src/utils.cpp

@@ -16,43 +16,39 @@ std::istream& StreamHandler::get_line(std::istream& stream, std::string& line) {
 }
 
 std::istream& StreamHandler::get_next_non_blank_line(std::istream& stream, std::string& line) {
-	bool is_blank = true;
 
-	const std::regex whitespace_re("\\s*(.*)");
-	std::smatch match;
+	// NOTE:
+	// The test expects this function to return a blank string if it has reached the end.
+	// IMO this behaviour is incorrect and it should always return the last valid string.
+	//  - S. Cahill.
 
-	while (is_blank) {
-		Utils::StreamHandler::get_line(stream, line);
+	for (;;) {
+        Utils::StreamHandler::get_line(stream, line);  // must strip trailing '\r'
 
-		std::regex_search(line, match, whitespace_re);
+        if (!stream) {                    // EOF or error after attempt to read
+            line.clear();                 // test expects "" at/after EOF; remove me if the behaviour is to be fixed.
+            return stream;
+        }
 
-		if ((!line.empty() && !match.empty()) || (stream.eof())) {
-			if ((match.length(1) > 0) || (stream.eof())) {
-				is_blank = false;
-			}
-		}
-	}
-
-	return stream;
+        if (!Utils::isWhitespaceOrEmpty(line)) {
+            return stream;                // found a non-blank line
+        }
+    }
 }
 
 std::istream& StreamHandler::skip_to_next_blank_line(std::istream& stream, std::string& line) {
-	bool line_is_empty = false;
-
-	const std::regex whitespace_re("\\s*(.*)");
-	std::smatch match;
+	for (;;) {
+        Utils::StreamHandler::get_line(stream, line);  // must strip trailing '\r'
 
-	while (!line_is_empty) {
-		Utils::StreamHandler::get_line(stream, line);
+        if (!stream) {                    // EOF or error after attempt to read
+            line.clear();                 // test expects "" at/after EOF; remove me if the behaviour is to be fixed.
+            return stream;
+        }
 
-		std::regex_search(line, match, whitespace_re);
-
-		if ((match.length(1) == 0) || (stream.eof())) {
-			line_is_empty = true;
-		}
-	}
-
-	return stream;
+        if (Utils::isWhitespaceOrEmpty(line)) {
+            return stream;                // found a blank line
+        }
+    }
 }
 
 double String::convert_to_double(const std::string& value, double default_value) {